Optical disc device

1. An optical disc apparatus, comprising: a disc rotation mechanism for allowing an optical disc having an information recording face to be placed thereon and rotating the optical disc; an optical pickup including an engaging section and irradiating the information recording face with a light beam to perform at least one of information recording and information reproduction; a base main body for rotatably supporting the optical pickup and having the disc rotation mechanism; a driving source, supported by the base main body, for generating a force for rotating the optical pickup; and a driving force transmission mechanism supported by the base main body, including a worm, and engaged with the engaging section to transmit a driving force of the driving source to the optical pickup, thereby rotating the optical pickup; wherein a distance between the engaging section and a rotating axis of the optical pickup is longer than a distance between the center of gravity of the optical pickup and the rotating axis of the optical pickup; and the driving force transmission mechanism includes a worm wheel engageable with the worm and driven by the worm, and where the advancing angle of the worm is θand a static coefficient of friction for the worm is μ, tan θ<μ.

2. The optical disc apparatus of claim 1 , wherein: the base main body includes a base shaft for rotatably holding the optical pickup; the optical pickup includes a pickup rotating hole for allowing the base shaft to be inserted thereto and having a bottom; and the base main body includes a shaft forcing part for forcing the optical pickup toward the base main body at a general axis of the base shaft in the state where the base shaft is inserted into the pickup rotating hole.

3. The optical disc apparatus of claim 1 , wherein the optical pickup includes a weight in an area located opposite to the center of gravity of the optical pickup with respect to the rotating axis.

4. The optical disc apparatus of claim 1 , wherein the base main body includes: a first base including a first regulating part for rotatably supporting the optical pickup and regulating a movement of the optical pickup in a direction of the rotating axis; and a second base including a second regulating part for supporting the driving source and the driving force transmission mechanism and regulating a movement of the engaging section in the direction of the rotating axis.

5. The optical disc apparatus of claim 4 , wherein: the first base includes a base shaft for rotatably supporting the optical pickup and a shaft forcing part; the optical pickup includes a pickup rotating hole for allowing the base shaft to be inserted thereto and having a bottom; and the shaft forcing part forces the optical pickup toward the first base at a general axis of the base shaft in the state where the base shaft is inserted into the pickup rotating hole.

6. The optical disc apparatus of claim 4 , wherein the second base is formed of a material having a lower specific gravity than that of the first base.

7. The optical disc apparatus of claim 1 , wherein: the optical pickup includes a pickup rotating hole outer cylinder projecting on the rotating axis, a pickup rotating hole provided inside the pickup rotating hole outer cylinder, a support boss projecting in the direction of the rotating axis on the opposite side to the pickup rotating hole outer cylinder, and a space provided between the pickup rotating hole outer cylinder and the support boss; and the base main body includes a first base having a support hole for receiving the support boss and a second base having a base shaft insertable into the pickup rotating hole.

8. The optical disc apparatus of claim 7 , wherein the optical pickup includes an optical system including a light source, an optical element, and an objective lens; and an optical path of the optical system crosses the space.

9. An optical disc apparatus, comprising: a disc rotation mechanism for allowing an optical disc having an information recording face to be placed thereon and rotating the optical disc; an optical pickup including an engaging section and irradiating the information recording face with a light beam to perform at least one of information recording and information reproduction; a base main body for rotatably supporting the optical pickup and having the disc rotation mechanism; a driving source, supported by the base main body, for generating a force for rotating the optical pickup; and a driving force transmission mechanism supported by the base main body, including a worm, and engaged with the engaging section to transmit a driving force of the driving source to the optical pickup, thereby rotating the optical pickup; wherein a distance between the engaging section and a rotating axis of the optical pickup is longer than a distance between the center of gravity of the optical pickup and the rotating axis of the optical pickup; the base main body includes a base shaft for rotatably holding the optical pickup; the optical pickup includes a pickup rotating hole for allowing the base shaft to be inserted thereto and having a bottom; the base main body includes a shaft forcing part for forcing the optical pickup toward the base main body at a general axis of the base shaft in the state where the base shaft is inserted into the pickup rotating hole; the base shaft has a tip contactable with the bottom of the pickup rotating hole; and the tip of the base shaft has a convexed spherical shape, and the bottom of the pickup rotating hole has a concaved spherical shape.

10. The optical disc apparatus of claim 9 , wherein: the base main body includes an engaging section forcing part for forcing optical pickup at the engaging section or the vicinity thereof toward a main surface of the base main body; and the optical pickup includes a roller contactable with the engaging section forcing part of the base main body and having a rotation axis in a direction perpendicular to the rotating axis of the optical pickup.

11. The optical disc apparatus of claim 9 , wherein: the spherical shape of the bottom of the pickup rotating hole has a radius larger than a radius of the spherical shape of the tip of the base shaft; and the bottom of the pickup rotating hole and the tip of the base shaft contact each other to determine the height of the optical pickup from the base main body.

12. The optical disc apparatus of claim 11 , wherein: the base main body includes a pickup holding section for, when at least one of the optical pickup, the base shaft and the base main body receives an external force, contacting the optical pickup so as to inhibit an axis of the base shaft from being inclined beyond a prescribed range and thus deformed.

13. The optical disc apparatus of claim 12 , wherein the optical pickup includes a support boss provided coaxially with the rotating axis and projecting on the opposite side to the pickup rotating hole, and the pickup holding section inhibits the support boss from being inclined beyond a prescribed range and thus deformed.

14. The optical disc apparatus of claim 13 , wherein the pickup holding section inhibits the optical pickup from moving away from the base main body beyond a prescribed range.

15. An optical disc apparatus, comprising: a disc rotation mechanism for allowing an optical disc having an information recording face to be placed thereon and rotating the optical disc; an optical pickup including an engaging section and irradiating the information recording face with a light beam to perform at least one of information recording and information reproduction; a base main body for rotatably supporting the optical pickup and having the disc rotation mechanism; a driving source, supported by the base main body, for generating a force for rotating the optical pickup; and a driving force transmission mechanism supported by the base main body, including a worm, and engaged with the engaging section to transmit a driving force of the driving source to the optical pickup, thereby rotating the optical pickup; wherein a distance between the engaging section and a rotating axis of the optical pickup is longer than a distance between the center of gravity of the optical pickup and the rotating axis of the optical pickup; wherein the base main body includes: a first base including a first regulating part for rotatably supporting the optical pickup and regulating a movement of the optical pickup in a direction of the rotating axis; and a second base including a second regulating part for supporting the driving source and the driving force transmission mechanism and regulating a movement of the engaging section in the direction of the rotating axis; wherein: the first base includes a base shaft for rotatably supporting the optical pickup and a shaft forcing part; the optical pickup includes a pickup rotating hole for allowing the base shaft to be inserted thereto and having a bottom; the shaft forcing part forces the optical pickup toward the first base at a general axis of the base shaft in the state where the base shaft is inserted into the pickup rotating hole; and the disc rotation mechanism includes an attaching base face facing a main surface of the first base, and the attaching base face is interposed between the first base and the second base.